Yes, been putting the app through its paces using the Alesis IO Dock 2. First impressions: great! I really like the package of the app, well laid out, can be used in a fairly simple way or if you want to dig deeper re editing you can. Five simultaneous effects, an xy pad and a sequencer to vary effects over time.
This app is going to take some getting used to, as is the dock, but it is showing great potential. Sonically I am very impressed.
I have been using a Zoom B3 a bit, and so am using that as a vague reference point. Flux doesn't have the amp/cab simulations and has fewer effects in each class, but that shouldn't be considered as a problem. As with gentle tweaking and storing one can get a good palette of sounds. What I do like is the ability to jump from Flux FX on my iPad to Garageband to my tuner..... Its good to have everything at hand. Using the 'Audiobus' app and others like it, it is possible to link Flux up with other apps which really make it very flexible. So you can drive Flux FX with say Moog Animoog synth app and send it either out to your amp or send it to another app on your iPad i.e. Garageband....... I'm beginning to see how it is a way of working as much as it is about a new effects unit. So far so good!